"I live on good soup, not on fine words."
Moliere (French Playwright, 1622-1673)
Moliere (French Playwright, 1622-1673)
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| Soup's On! French onion soup. |
I know all you people in the states are going to be laughing at me, but I have a hankering for soup. Yes, I do realize that it’s 60 degrees in New York City. And my mother just called me to say that she’s been playing golf for the nth day straight…in Chicago.
But here in Copenhagen, the date says spring…but the weather? Let’s put it this way…we haven’t packed our winter jackets away. And my three-week cold from hell hasn’t gone away either, so soup it is, but not any soup…French onion soup.
I’d like to think of French onion soup akin to the Gogo Yubari[1] from Kill Bill Vol. 1. You think it’s going to be nice light and easy, and then, BAM! Knocks you out with 2 for 1 punch of umami-caramel goodness.
Why is it so damn good? Well, for starters, it has to do with the onions. The carmelization of onions give it the bittersweet base. The beef broth gives some savoriness to the base. Some alcohol balances the sweetness. And the cheese crouton adds the final umami punch. It’s a flavor no-brainer.
The base of ANY good French onion soup is the caramelization of onions. And lest you think that caramel was only for apples, dessert & Halloween, you’re on notice. Browning on French Fries? That’s caramelization. Roasted sweet potatoes? That’s also caramelization. Along with the Maillard reaction[2], it’s one of the critical chemical reactions in cooking that is truly transformative.
Caramelization at the heart of it is simply the chemical breakdown of sugar into new compounds via pyrolysis[3], otherwise known as heat & chemistry. Any sugar will do: fructose (fruit sugar), lactose (milk sugar), sucrose (beet & cane sugars – the white stuff you buy at the grocery), or maltose (the sugar in barley that is used in making beer). Sugar, unlike proteins, is incredibly stable – they will not oxidize, denature, coagulate…basically all the chemical reactions that spoil food. But the one thing that gets sugar moving? Heat. By heating sugar, the water is evaporated out of the sugar and starts to break down creating new compounds that contribute to browning, bitterness, aromas, sourness and nuttiness.
But it takes a lot of heat to get that reaction going. Fructose (in fruits like apples, bananas, pineapples, etc) and glucose (grape sugar) will caramelize at relatively low temperatures, 220°F and 300°F, respectively, due to their chemical makeup (they have free electrons to donate, thus making it easier to react to heat). Sucrose, on the other hand, is a much more complex (it’s basically a fructose molecule attached to a glucose molecule via their free electrons) and much more difficult to break apart – thus the higher temperature needed to start caramelization, around 340°F.
But what does this have to do with onions? Yes, onions raw have a distinct sharpness (that’s from the volatility of sulfur compounds in onions), but their high sugar content, in the form of fructose, is what we want them for in French onion soup. And the characteristic nutty, rich flavor is dependent upon caramelization and the Maillard process. But this process is not a straightforward one. Because onions are 75% water, neither process can begin without the water being evaporated first. Only until the onions are “sweated” out, in which the onion cells burst and release their water, AND the temperature reaches around 220°F (the temperature at which fructose caramelizes) will both processes start.
And that’s when you start to see browning in your onions. However, the process is not a quick one. The key with caramelizing onions is really going low and slow. Can you speed it up? Not really. Why? Turn up the heat, and your onions will char-raw and you will not pass go or collect 200. You will have to start all over again. You can change the pH of your onions, by adding baking soda (alkaline) to speed up the Maillard reaction, but it will give a chemical aftertaste. That’s no good either.
But you can add a pinch of salt. Why? Salt leeches water out of cells and that will help speed up the evaporation process. Some people add sugar as well, but beyond sweetening the onions a tad bit, it will do very little to speed up the process, mainly because sucrose (table sugar is sucrose) requires more energy (heat) to caramelize thus increasing the possibility that your onions might burn.
So what’s a time strapped person to do? Sorry…there are no short cuts here. It’s going to take you a full 1-2 hours, dependent upon the amount, (and if you go the Thomas Keller route, another 3 more) for onions to caramelize properly. Anyone that tells you that it’s going to take a shorter amount of time is fooling you. You are going to have to have some serious time on your hands. But the good news is that once you’ve made the onions, the rest of the process is pretty simple. You just need some booze to deglaze (I’m partial to cognac, sherry or calvados), good beef stock (or if you don’t have that, get some low sodium vacuum packed stock[4]), some Gruyere and stale bread and you are good to go. Even though you aren’t in France, at least you can eat like you are. And that is worth 3 hours of anyone’s time.
French Onion Soup
One more note – the more aged your Gruyere, the better. The Gruyere gives the necessary counterbalance to all sweetness in the soup. Also, don’t freak out about the vinegar. It’s pretty traditional in France to add a touch to the soup to balance it out both the sugar and the fat from the cheese. And if you don’t believe me about the amount of time it takes to caramelize the onions…just look at the pictures.
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| Time 0. Onions straight into the pot. |
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| 20 Minutes. No browning, but a lot of sweating going on. |
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| 45 minutes. Still no caramelization. |
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| Hour and 10 minutes. Ah! There's color! |
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| We're at 1 hour and a half. Looking good. |
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| 2 hours. Finally. Freaking. DONE! |
Serves 6-8 as a starter or 4 as a main course
4 tbs. butter
2 tbs. olive oil
8 large onions, thinly sliced into half moons
1 sprig of thyme
8 c. beef broth (preferably homemade)
¼ c. dry sherry
dash of calvados (if you don’t have any, any other good brandy or cognac is ok)
2 tbs. sherry vinegar (you can use balsamic as well)
8 slices of day-old good white bread (peasant bread or baguette are good choices)
1 clove of garlic, halved
6-8 oz of aged Gruyere, shredded
1. Heat butter and olive oil in a large heavy skillet or Dutch oven (NOT non-stick or cast iron) over medium-low heat. Add onions, pinch of salt, and cook until caramelized and deep brown, stirring often. If the onions stick to the bottom of the pan, add a dash of water, loosen onions (like deglazing a pan for sauce) and continue. This will take a minimum of 1 ½ hours…probably closer to 2 (see pictures).
2. Add sherry and scrape any browned bits off the bottom of the pan. If you are using a skillet, transfer onions to a stockpot (if you use a Dutch oven, you can just leave them in the pan). Add beef broth, thyme and sherry vinegar to onions. Turn up the heat to medium high and bring to a boil. Once at a boil, turn down heat and let soup simmer for 45 minutes.
3. In the meanwhile, rub cut sides of garlic on bread slices. Place in a 350F oven until toasted (it will take about 2-3 minutes).
4. Add calvados and check for seasoning (it will probably need a good pinch of salt). Ladle soup into ovenproof bowls, top with slice of bread (use 2 slices if you’re using a baguette-they’re small) and sprinkle cheese on top. Place under your oven broiler until the cheese is bubbly and golden brown. Serve immediately.
Vegetarians: This soup can be made vegetarian by omitting beef broth and using vegetable broth instead.
NB: Just like anything else that is heated in an oven, the bowls are going to be PIPING hot as well as the soup inside it. Be VERY careful taking bowls out of the oven and please warn your guests that the bowls are very hot. We’re talking 3rd degree burns here.
[1] Just in case you haven’t remembered who this is, Gogo Yubari is the apprentice of O-ren Ishii. O-Ren is the Asian chick of the Deadly Viper Assassination Squad (played by Lucy Liu in the movie).
[2] It’s the nitrogen and sulfur in amino acids in meat that give cooked meat it’s distinctively “meaty” smell and flavor when heated, unlike sugars which are always a combination of oxygen, hydrogen and carbon.
[3] Pyrolysis is from the Greek, “pyr” for fire and “lysis” to separate.
[4] I’m not being picky for no reason. Canned stock has BPA (Bisphenol A) in their liners. Unless you want reproductive problems, stay away from the stuff. The vacuum packed stock has no BPA’s in it. Trader Joe’s makes a nice organic one that tastes reasonably good.
